A United Nations report criticising the Cambodian administration of the Khmer Rouge trials has been made public.
The report says the special courts are employing unqualified staff at inflated salaries, without a proper recruitment process.
It recommends that the UN pull out of the process if changes are not made.
The courts are probing allegations of genocide by the Khmer Rouge. More than one million people are thought to have died during the regime's 1975-79 rule.
'Unbalanced account'
The audit says the courts are spending hundreds of thousands of dollars on staff who should not have been employed. It described more than 50 as "excess" hirings beyond the original budget and it said that more than half of the courts' Cambodian employees did not have the required qualifications or experience.
All Cambodian staff contracts should be cancelled and the recruitment process re-started from scratch.
The United Nations Development Programme says that "serious consideration should be given to withdrawing from the project", if the Cambodian administration refuses to address its concerns.
In response, the Cambodian side has called the audit an "unbalanced account" and its recommendations "out of proportion".
It says that great achievements have been made despite major difficulties and that many problems could have been averted with more assistance from the UN.
The Open Society Justice Initiative, which is monitoring the courts, has welcomed the report's publication.
But the organisation said it was disappointed that the report had not looked into other allegations of corruption.
The Justice Initiative claimed in February that Cambodian staff were paying part of their salaries to superiors in return for being hired.
